[Python-Dev] seeing off SET_LINENO

[Michael Hudson]

Guido van Rossum <guido@python.org> writes:

> > pystone is a mystery.  It's a fair bit slower but also much more
> > variable with my patch.  Moving trace code out of line helps quite a
> > bit but it's still ~1% slower.
> 
> Hm.  For me (with your latest patch which moves the trace code out of
> line) pystone is actually *less* variable with your patch than
> without, and it's also faster with -O than before.
> 
> So I wouldn't lose any sleep over pystone (leave that to Tim :-).

I wasn't going to.

> Maybe you should increase LOOPS in pystone.py; I usually set it to 40K
> or even 100K.

Did that.  I thought measuring 0.8 secs was a bit on the thin side.

[...]
> > Also, it seems Lib/compiler currently works by generating SET_LINENO
> > and then builds co_lnotab by scanning for them afterwards.  That's not
> > going to work in the new world, so I should probably think about how
> > to change it...
> 
> Or wait for Jeremy.

Yes.

> (I suppose you still *support* the SET_LINENO opcode?)

No.  Do you think I should?

> BTW, you should change the .pyc magic number in your patch.

Really?  It's already changed since the last released Python.  Easy
enough to change again, though, and it makes testing easier.

Cheers,
M.

-- 
  You have run into the classic Dmachine problem: your machine has
  become occupied by a malevolent spirit.  Replacing hardware or
  software will not fix this - you need an exorcist. 
                                       -- Tim Bradshaw, comp.lang.lisp